JP2005028137A - Centrifugal liquid pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal liquid pump device that can rotate an impeller without making the impeller touch the inner surface of a housing using a pressure generated by a dynamic bearing and can maintain supplying a liquid when a trouble occurs in a control mechanism of a magnetic bearing. <P>SOLUTION: This centrifugal liquid pump device 1 comprises a pump main body 5 provided with a pump section 2 having an impeller 21 rotating in a housing 20, a rotor 31 having a magnet 33, a motor 34 rotating the rotor, an electromagnet 41 for attracting the impeller, an impeller position detection sensor 42, and a dynamic bearing means 38 formed on the inner surface of the housing 20, and a control mechanism 6. The control mechanism 6 has a position sensor output monitoring function 56, an electromagnet electric current monitoring function 57, and a motor current monitoring function, and has an emergency impeller rotation function that judges a sensor malfunction or an electromagnet malfunction by using the position sensor output monitoring function and the electromagnet current monitoring function, functions at the time of detection of the malfunction, and rotates the impeller by using the dynamic bearing means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a centrifugal liquid pump device, and more particularly to a centrifugal liquid pump device for feeding a medical liquid such as blood.

  In recent medical treatments, an example in which a centrifugal blood pump is used for extracorporeal blood circulation in an oxygenator is increasing. As a centrifugal pump, the physical communication between the outside and the blood chamber in the pump is completely eliminated, and invasion of bacteria and the like can be prevented, so that the driving torque from the external motor is transmitted to the impeller using magnetic coupling. The system of the method to be used is used. Such a centrifugal blood pump has a housing having a blood inflow port and a blood outflow port, and an impeller that rotates within the housing and feeds blood by centrifugal force during rotation. The impeller is rotated by a rotational torque generating mechanism including a rotor including a magnet for attracting a permanent magnet provided therein and a motor for rotating the rotor. The impeller is also attracted by the magnetic force on the side opposite to the rotor, and rotates in a non-contact state with respect to the housing. This state is called a magnetic levitation state.

However, in a centrifugal pump using a conventional magnetic bearing, when a failure, that is, malfunction occurs in the control system of the magnetic bearing, the impeller cannot be rotated to maintain the pump function.
This magnetic levitation type centrifugal pump includes three impeller position sensors and three impeller suction electromagnets. In the control of the magnetic bearing in the centrifugal pump, the position of the impeller is controlled by controlling the current supplied to the electromagnet according to the information of the impeller position sensor. Therefore, when a device constituting this control system fails, for example, when a position sensor cable or an electromagnet cable is disconnected, the control system fails and correct control cannot be performed. Therefore, under such circumstances, it becomes difficult to rotate the impeller by the magnetic bearing in the magnetic levitation state.

  The object of the present invention is to rotate the impeller in a substantially non-contact state between the impeller and the inner surface of the housing by the pressure generated by the hydrodynamic bearing when the control mechanism of the magnetic bearing is broken or malfunctioned, thereby Another object of the present invention is to provide a centrifugal liquid pump capable of maintaining liquid feeding.

What achieves the above object is as follows.
(1) A centrifugal liquid pump device having a pump body in which an impeller rotates without contacting a housing, and a control mechanism for the pump body,
The pump body includes the housing having a liquid inflow port and a liquid outflow port, a first magnetic body, and a second magnetic body, and rotates the liquid in the housing by centrifugal force generated during rotation. A centrifugal pump unit having the impeller for feeding liquid, a rotor having a magnet for attracting the first magnetic body of the impeller, an impeller rotational torque generating unit having a motor for rotating the rotor, and the impeller An impeller position control unit having an electromagnet for attracting the second magnetic body, a position sensor for detecting the position of the impeller, an inner surface of the housing on the rotor side, or the rotor side of the impeller Hydrodynamic bearing means provided on the surface,
The control mechanism uses a position sensor output monitoring function or an electromagnetic current monitoring function, a motor current monitoring function, and the position sensor output monitoring function to determine a failure of the sensor, or the electromagnetic current monitoring function. A failure detection function for determining a failure of the electromagnet using the dynamic pressure bearing means when the failure detection function detects a failure of the sensor or when the failure detection function detects a failure of the electromagnet. An impeller rotating function for emergency that acts to rotate the impeller without substantial contact between the impeller and the housing,
The emergency impeller rotation function includes: a rotation stop function that stops supply of power to the motor and the electromagnet and stops rotation of the rotor and the impeller when the failure detection function detects a failure; and the magnet The impeller magnetic attraction force applying function that supplies the electromagnet with a current large enough to overcome the magnetic coupling force of the rotor generated by the impeller and the motor current monitored by the motor current monitoring function is used. Then, the dynamic pressure levitation control detection function for detecting the dynamic pressure bearing coupling and thereby detecting the magnetic rotation coupling of the impeller and the rotor under the dynamic pressure bearing condition, and the dynamic pressure levitation control detection function include the impeller And detecting that the hydrodynamic bearing coupling is formed between the rotors, and increasing the motor speed, Accordingly, a motor speed control function for increasing the impeller rotational speed to a predetermined value, and an impeller magnetic attractive force stop function for stopping the supply of current to the electromagnet when the impeller rotational speed reaches the predetermined value. A centrifugal liquid pump apparatus.

(2) The control mechanism has the position sensor output monitoring function and the electromagnet current monitoring function, and the failure detection function is capable of determining a failure of the sensor and a failure of the electromagnet. A centrifugal liquid pump device according to 1).
(3) The centrifugal liquid pump device includes a sensor circuit for the sensor, and the sensor circuit has a function of generating an output having a predetermined value exceeding a normal level when the position sensor is disconnected. The centrifugal liquid according to (1) or (2), wherein the failure detection function determines whether or not the sensor is in failure based on the output of the sensor monitored by the sensor output monitoring function. Pump device.

(4) The centrifugal liquid pump device includes the electromagnet circuit, the electromagnet circuit is disconnected when the electromagnet is disconnected, and the failure detection function includes the electromagnet current monitoring function, The centrifugal liquid pump device according to any one of (1) to (3), wherein when it is determined that no current is flowing in the electromagnet circuit, the electromagnet is determined to be faulty.
(5) When the failure detection function detects a failure, the emergency impeller rotation function balances the magnetic coupling force between the magnet and the impeller of the rotor and the attraction generated by the electromagnet, The centrifugal liquid pump device according to any one of (1) to (4), wherein the impeller is rotated.

(6) The centrifugal liquid pump device according to any one of (1) to (5), wherein the dynamic pressure bearing means has at least one groove provided on an inner surface of the housing on the rotor side. .
(7) The centrifugal liquid pump device according to any one of (1) to (5), wherein the dynamic pressure bearing means has at least one groove provided on a surface of the impeller on the rotor side. .
(8) The centrifugal liquid pump device according to any one of (1) to (5), wherein the dynamic pressure bearing means has a plurality of steps provided on a surface of the impeller on the rotor side.
(9) The impeller magnetic attraction force applying function is to apply a first continuous current to the electromagnet to form attraction, and to apply a predetermined voltage to the motor to try to rotate the impeller. The centrifugal liquid pump device according to any one of 1) to (8).
(10) The impeller magnetic attractive force imparting function may further include applying a second continuous current to the electromagnet when the motor fails to rotate the impeller after the first trial. And the predetermined voltage is applied to the motor to try to rotate the impeller. The second continuous current is obtained by the attraction force formed by the second continuous current. The centrifugal liquid pump device according to (9), wherein the second continuous current is larger than the first continuous current so as to be greater than the suction force formed by the continuous current.

(11) The centrifugal liquid pump device according to (10), wherein the second continuous current is larger than the first continuous current by a predetermined step value.
(12) The impeller magnetic attractive force imparting function may further include applying an increased continuous current to the electromagnet when the motor fails to rotate the impeller after the first trial and the second trial. The attraction force is formed, and the impeller is repeatedly rotated by applying the predetermined voltage to the motor. The increased continuous current is obtained by rotating the impeller or the increased continuous current reaches a predetermined maximum value. The centrifugal liquid pump device according to (11), wherein the increase is repeated by the predetermined step until reaching.

(13) The centrifugal liquid pump device according to (12), wherein the first continuous current is a current corresponding to a time duty cycle of 10% of pulse width modulation control.
(14) The centrifugal liquid pump device according to (12), wherein the predetermined step value is 1%.
(15) The centrifugal liquid pump device according to (12), wherein the predetermined maximum value of the increased continuous current is about 20% in time.
(16) The pump body includes a plurality of the electromagnets, the electromagnet current monitoring function monitors currents of the electromagnets, and the failure detection function determines at least a failure of the electromagnets. The impeller magnetic attractive force imparting function in the emergency impeller rotating function is performed using an electromagnet that is not out of the plurality of electromagnets, and is any one of (1) to (15). Centrifugal liquid pump device.

  According to the centrifugal liquid pump apparatus of the present invention, when a trouble occurs in the position sensor or the electromagnet constituting the control system of the magnetic bearing, and the trouble or other malfunction occurs, the dynamic pressure bearing starts from the rotation of the impeller by the magnetic bearing. It is possible to shift to rotation using the pressure generated by the groove. Therefore, liquid feeding can be maintained.

An embodiment of a centrifugal liquid pump device according to the present invention will be described with reference to the accompanying drawings.
The centrifugal liquid pump device of the present invention is indicated by reference numeral 1 in its entirety.
The centrifugal liquid pump device 1 includes a pump body 5 and a control mechanism 6 of the pump body 5, and the impeller 21 rotates without contacting the housing 20 inside the pump body 5.
2 to 6, the pump body 5 includes a housing 20 having a blood inflow port 22 and a blood outflow port 23, a first magnetic body 25 and a second magnetic body 28 therein, and rotates within the housing 20. The rotor 31 and the rotor 31 including the centrifugal liquid pump unit 2 having the impeller 21 for feeding the liquid by the centrifugal force at the time of rotation and the magnet 33 for attracting the first magnetic body 25 of the impeller 21 are rotated. For detecting the position of the impeller rotational torque generating section 3 having a motor 34 for causing the impeller 21, the electromagnet 41 for attracting the impeller 21 (the electromagnet for attracting the second magnetic body 28 of the impeller 21), and the impeller 21. Position sensor 42 (position sensor for detecting the position of the second magnetic body 28 of the impeller 21), and the inner side of the housing 20 on the rotor 31 side. Or and a impeller position control section 4 having the dynamic pressure bearing groove 38 provided on the surface of the rotor 31 side of the impeller 21.

The control mechanism 6 includes a motor current monitoring function, a position sensor output monitoring unit (position sensor output monitoring function) 56 or an electromagnet current monitoring function 57, and a failure detection function. The failure detection function determines the failure of the position sensor 42 using the position sensor output monitoring function, or determines the failure of the electromagnet 41 using the electromagnet current monitoring function.
As shown in FIG. 1, the control mechanism 6 uses the position sensor output monitoring function 56, the electromagnet current monitoring function 57, the motor current monitoring function, and the position sensor output monitoring function 56 to determine whether or not the position sensor has failed. And a failure detection function for determining whether or not the electromagnet has failed using the electromagnet current monitoring function 57.

The centrifugal liquid pump device 1 operates when a sensor failure is detected or an electromagnet failure is detected by a failure detection function, and the impeller 21 is rotated in a substantially non-contact state with respect to the housing 20 using the dynamic pressure bearing groove 38. It has an emergency impeller rotation function.
The emergency impeller rotation function includes a rotation stop function, an impeller magnetic attractive force application function, a dynamic pressure levitation control detection function, a motor speed control function, and an impeller magnetic attractive force stop function. The rotation stop function stops the supply of current to the motor and the electromagnet 41 when the failure detection function detects a failure and stops the rotation of the rotor 31 and the impeller 21. The impeller magnetic attraction force providing function supplies the electromagnet 41 with a current sufficient to overcome the magnetic attraction force to the impeller 21 of the rotor 31 generated by the permanent magnet. The dynamic pressure levitation stop control function uses the motor current monitored by the motor current monitoring function to generate a hydrodynamic bearing coupling between the impeller and the rotor, and that the impeller is rotating. It detects that the magnetorotational coupling has occurred under the bearing condition. The motor speed control function detects the occurrence of the hydrodynamic bearing coupling between the impeller and the rotor after the dynamic pressure levitation control detection function detects the speed of the impeller by increasing the motor speed (for example, gradually, ie, continuously (In step or step) to a predetermined value. The impeller magnetic attractive force stop function stops the supply of current to the electromagnet 41 when the rotation speed of the impeller reaches a predetermined value.

That is, the centrifugal liquid pump device 1 of the present invention is a non-contact (magnetic) rotary coupling of an impeller by a magnetic bearing when a sensor or an electromagnet breaks down. It has the function of shifting to (magnetic) rotational coupling.
In the rotation of the impeller by the dynamic pressure bearing groove, since there is the permanent magnet 33, it is generated by the magnetic attractive force acting between the impeller and the rotor and the dynamic pressure bearing groove acting in the direction opposite to the direction of the magnetic attractive force. It is necessary to balance the pressure. In order to do so, rotation of the impeller and the rotor is essential. Therefore, when the control system of the magnetic bearing breaks down and the impeller and the rotor are no longer in the magnetic levitation state, the imbalance of the permanent magnet 33 to the impeller is not achieved simply by machining the groove for controlling the dynamic pressure levitation. Due to the large attraction force generated by the attraction and the frictional force caused by the attraction, it is impossible to shift from the rotation by the magnetic bearing of the impeller to the rotation by the groove for the dynamic pressure bearing.

An embodiment of a centrifugal liquid pump apparatus of the type having the position sensor output monitoring function 56 and the electromagnet current monitoring function 57 shown in FIG. 1 and capable of judging the failure of the sensor and the electromagnet will be described.
As shown in FIGS. 2 to 6, the pump body 5 includes a housing 20 having a blood inflow port 22 and a blood outflow port 23, and an impeller 21 that rotates in the housing 20 and sends blood by centrifugal force during rotation. The centrifugal liquid pump unit 2 having the impeller 21, the impeller rotational torque generating unit 3 for the impeller 21, and the impeller position control unit 4 for the impeller 21 are provided.

As shown in FIG. 4, the impeller 21 is normally held at a predetermined position in the housing 20 by the action of the impeller rotational torque generation unit 3 and the impeller position control unit 4 and rotates without contacting the inner surface of the housing 20. .
The housing 20 has a blood inflow port 22 and a blood outflow port 23, and is formed of a nonmagnetic material. A blood chamber 24 communicating with the blood inflow port 22 and the blood outflow port 23 is formed in the housing 20. An impeller 21 is also accommodated in the housing 20. The blood inflow port 22 is provided so as to protrude substantially vertically from the vicinity of the center of the upper surface of the housing 20. As shown in FIGS. 3 and 5, the blood outflow port 23 is provided so as to protrude in a tangential direction from the side surface of the housing 20 formed in a substantially cylindrical shape.

  As shown in FIG. 5, a disc-like impeller 21 having a through-hole at the center is housed in a blood chamber 24 formed in the housing 20. As shown in FIG. 4, an impeller 21 of a preferred embodiment includes a donut plate-like member (lower shroud) 27 that forms a lower surface, a donut plate-like member (upper shroud) 28 that opens at the center and forms an upper surface, A plurality of (for example, seven) vanes 18 formed between the two. Between the lower shroud 27 and the upper shroud 28, a plurality of (for example, seven) blood passages 26 partitioned by the adjacent vanes 18 are formed. As shown in FIG. 5, each blood passage 26 communicates with the central opening of the impeller 21 and extends from the central opening of the impeller 21 to the outer edge so that the width gradually increases. In other words, the vane 18 is formed between the adjacent blood passages 26. In the present embodiment, the blood passages 26 and the vanes 18 are provided at equal angular intervals and in substantially the same shape.

As shown in FIG. 4, a plurality of (for example, 24) first magnetic bodies 25 (for example, permanent magnets and driven magnets) are embedded in the impeller 21. In the present embodiment, the first magnetic body 25 is embedded in the lower shroud 27. The embedded first magnetic body 25 has the impeller 21 on the side opposite to the blood inflow port 22 (in other words, on the rotor 31 side) by a permanent magnet 33 provided on the rotor 31 of the impeller rotational torque generating unit 3 described later. And the rotational torque is transmitted from the impeller rotational torque generator 3 to the impeller 21.
By embedding the plurality of first magnetic bodies 25 in the impeller 21, magnetic levitation coupling described later is ensured between the impeller 21 and the rotor 31. The first magnetic body 25 (permanent magnet) preferably has a circular cross section. However, a multi-pole (for example, 24 poles) ring-shaped magnet can also be used. In other words, a plurality of small magnets may be arranged in a ring shape so that the anode and the cathode are alternately arranged.

Further, the impeller 21 includes a second magnetic body 28 that itself constitutes the upper shroud or is provided in the upper shroud. In the present embodiment, the entire upper shroud is formed of the second magnetic body 28. The second magnetic body 28 is provided such that an electromagnet 41 of the impeller position control unit 4 described later magnetically attracts the impeller 21 toward the blood inflow port 22 side. The second magnetic body 28 is made of magnetic stainless steel.
The impeller position controller 4 and the impeller rotational torque generator 3 constitute a non-contact magnetic bearing and magnetically attract the impeller 21 from opposite directions. Therefore, the impeller 21 is securely held at an appropriate position not in contact with the inner surface of the housing 20, and rotates in a non-contact state with the inner surface in the housing 20.

As shown in FIG. 4, the impeller rotational torque generating unit 3 includes a rotor 31 housed in the housing 20 and a motor 34 for rotating the rotor 31. The rotor 31 includes a plurality of permanent magnets 33 provided on the surface on the centrifugal liquid pump unit 2 side. The central portion of the rotor 31 is fixed to the rotating shaft of the motor 34. The plurality of permanent magnets 33 are arranged at an equal angle so as to correspond to the arrangement form (number and arrangement position) of the permanent magnets 25 of the impeller 21.
The impeller rotational torque generating unit 3 is not limited to the one provided with the above-described rotor and motor. For example, as long as the permanent magnet 25 of the impeller 21 is attracted and the impeller 21 is rotationally driven, a plurality of stator coils can be used as the impeller rotational torque generating unit 3.

  As shown in FIGS. 3 and 4, the impeller position control unit 4 includes a plurality of electromagnets 41 that attract the second magnetic body 28 of the impeller 21, and the second magnetic body of the impeller 21. And a plurality of position sensors 42 for detecting 28 positions. The electromagnets 41 (three) and the position sensors 42 (three) are provided at equiangular intervals, and the electromagnet 41 and the position sensor 42 are also provided at equiangular intervals. The electromagnet 41 includes an iron core and a coil. In this embodiment, three electromagnets 41 are provided, but other numbers, for example, four may be provided. By adjusting the electromagnetic force of these electromagnets 41 using the detection result of the position sensor 42, the force in the rotation axis (z-axis) direction of the impeller 21 is balanced and the x-axis is orthogonal to the rotation axis (z-axis). And the moment about the y-axis can be controlled.

  The position sensor 42 detects the gap between the electromagnet 41 and the second magnetic body 28. The output of the position sensor 42 indicating the detection result is sent to the control unit 51 of the control mechanism 6 that controls the current (hereinafter referred to as electromagnet current) or voltage applied to the coil of the electromagnet 41. Even if a radial force such as gravity acts on the impeller 21, the restoring force of the magnetic flux between the permanent magnet 25 of the impeller 21 and the permanent magnet 33 of the rotor 31, and the electromagnet 41 and the second magnetic body 28 Therefore, the impeller 21 is held at the center of the housing 20.

  As shown in FIG. 6, in the centrifugal liquid pump device 1 of the present embodiment, the housing 20 accommodates the impeller 21 and includes a dynamic pressure bearing groove 38 provided on the inner surface 20 a of the housing 20 on the rotor 21 side. The housing inner surface 20 a forms a blood chamber 24. When the action of the magnetic bearing stops due to a failure or malfunction (in other words, when the operation of the electromagnet stops and the magnetic levitation state is lost), the impeller 21 maintains the rotation of the predetermined number of revolutions or more as described above. Then, a dynamic pressure floating effect is generated between the dynamic pressure bearing groove 38 and the impeller 21, and the bearing 20 rotates in a non-contact state with respect to the inner surface of the housing 20.

  As shown in FIG. 6, the hydrodynamic bearing groove 38 is formed to have a size corresponding to the bottom surface (the rotor side surface) of the impeller 21. In the centrifugal liquid pump device 1 of the present embodiment, the dynamic pressure bearing groove 38 has one end on the periphery of a circular portion slightly spaced outward from the center of the inner surface 20a of the housing 20, and its width is It extends outwardly in a spiral shape (in other words, in a curved shape) to the vicinity of the outer edge of the housing inner surface 20a so as to increase toward the outside. A plurality of dynamic pressure bearing grooves 38 are provided, each having substantially the same shape and arranged at substantially the same interval. The dynamic pressure bearing groove 38 is formed in a concave shape. The depth is preferably about 0.01 to 0.2 mm. The number of the dynamic pressure bearing grooves 38 is preferably about 6 to 36. In this embodiment, twelve dynamic pressure bearing grooves 38 are arranged at equal angles around the central axis of the impeller 21.

The dynamic pressure bearing groove 38 may be provided not on the housing 20 but on the surface of the impeller 21 on the rotor 21 side. The dynamic pressure bearing groove 38 in this case also preferably has the same configuration as the dynamic pressure bearing groove 38 disposed on the surface of the housing 20.
The dynamic pressure bearing groove 38 having such a configuration is attracted to the impeller rotational torque generating unit 3 side when the impeller position control unit 4 is not operated. Due to the dynamic pressure bearing effect formed between the dynamic pressure bearing groove 38 and the bottom surface of the impeller 21 (or between the dynamic pressure bearing groove and the inner surface of the housing), the impeller 21 is slightly separated from the inner surface of the housing 20. It rotates in a non-contact state with respect to the inner surface of the housing 20 to secure a blood flow path between the lower surface of the impeller 21 and the inner surface of the housing 20. This prevents the accumulation of blood between them and the generation of thrombus caused by this. Further, in a normal state, the dynamic pressure bearing groove 38 has a stirring action between the lower surface of the impeller 21 and the inner surface of the housing 20, and can prevent partial blood retention between the two.

  In FIG. 1, the control mechanism 6 monitors a current applied to (flows through) the power amplifier 52 for the magnetic coupling motor 34, the motor control circuit 53, the power amplifier 54 for the electromagnet 41, and the electromagnet 41. An electromagnet current monitoring unit 57, a sensor circuit 55 for the position sensor 42, a position sensor output monitoring unit 56 for monitoring the output of the sensor 42, and a control unit 51 are provided. The control unit 51 has a motor current monitoring function.

In the present embodiment, the control mechanism 6 includes the electromagnet current monitoring unit 57 and the sensor output monitoring unit 56, but may include only one of them.
When the failure detection function detects that the sensor or the electromagnet has failed, the centrifugal liquid pump device 1 uses the dynamic pressure bearing groove 38 to rotate the impeller 21 in a non-contact state with respect to the housing 20. It has an emergency impeller rotation function that acts on.
The control unit 51 has a failure detection function, a rotation stop function, an impeller magnetic attractive force application function, a dynamic pressure levitation control detection function, a motor speed control function, and an impeller magnetic attractive force stop function. The failure detection function determines a sensor failure based on the output of the electromagnet current monitoring unit or the output of the sensor output monitoring unit. The rotation stop function stops power to the motor and the electromagnet 41 and stops the rotation of the rotor 31 and the impeller 21 when the failure detection function detects a failure. The impeller magnetic attraction force applying function applies to the electromagnet 41 a current large enough to overcome the magnetic attraction force of the permanent magnet 33 to the impeller 21 of the rotor 31. The dynamic pressure levitation control detection function detects the rotation of the impeller and the rotor by using the motor current monitored by the motor current monitoring function. The motor speed control function detects that the hydrodynamic bearing coupling has been established between the impeller and the rotor, and then increases the motor speed to increase the impeller rotational speed to a predetermined value (for example, gradually, i.e., , Continuously or step by step). The impeller magnetic attractive force stop function stops the supply of current to the electromagnet 41 when the impeller reaches a predetermined rotational speed.

The control mechanism 6 of the centrifugal pump of this embodiment has a position sensor output monitoring function and an electromagnet current monitoring function. When the control mechanism 6 detects that the output of the position sensor (provided with a plurality of systems) or the electromagnet current (provided with a plurality of systems) deviates from the normal range, The control mechanism 6 shifts the non-contact rotation of the impeller by the magnetic bearing to the non-contact rotation by the dynamic pressure bearing groove 38 (which means that the magnetic bearing cannot be controlled because the magnetic levitation is impossible).
When a failure occurs in a sensor system of a magnetic bearing due to device breakage or cable disconnection, the sensor output deviates from the normal range. For example, when the reluctance sensor is disconnected, the sensor output deviates from the normal range.
For this reason, the centrifugal liquid pump device of this embodiment has a sensor circuit having a function of generating a predetermined output value exceeding the normal level when a disconnection occurs in the sensor system. Specifically, when the sensor circuit output is normally in the range of −1 to +1 [V] as the sensor output, the sensor circuit output is +2.5 [V] (predetermined value) when the sensor system is disconnected. It becomes. Therefore, the failure detection function can easily and reliably determine that the sensor is in failure (disconnection) when the output value of the sensor by the sensor output monitoring function is equal to the output value when the sensor system is disconnected.

  Similar to the sensor system, when a failure occurs due to device breakage or cable breakage in the electromagnet current system, the current applied (flowing) to the electromagnet current system deviates from the normal range. Therefore, the centrifugal liquid pump device of this embodiment includes a circuit for an electromagnet. The electromagnet circuit of this embodiment is of a type that is disconnected when the electromagnet is disconnected. Specifically, the range of current applied (flowing) to the electromagnet circuit is usually 1 to 2 [A]. When disconnection occurs in the electromagnet circuit, the current becomes 0 [A]. Therefore, the failure detection function can easily and reliably determine the failure (disconnection) of the electromagnet when it is monitored by the electromagnet current monitoring function that no current flows through the electromagnet circuit.

  The centrifugal liquid pump apparatus of this embodiment includes a plurality of electromagnets. The electromagnet monitoring function monitors the current of each electromagnet. When any one of the electromagnets has a failure, the failure detection function determines that the electromagnet has a failure. Similarly, the centrifugal liquid pump device of the present embodiment includes a plurality of position sensors. The sensor output monitoring function monitors the output of each sensor. Then, when a failure occurs in any one of the sensors, the failure detection function determines that the position sensor is in failure.

  The dynamic pressure bearing including the dynamic pressure levitation control groove is a system in which the impeller 21 and the housing 20 are held in a non-contact manner by pressure generated by the dynamic pressure bearing groove, thereby establishing a dynamic pressure bearing coupling. However, to allow rotation, the magnetic coupling between the impeller and the rotor must be normal. When a failure occurs in the control mechanism of the magnetic bearing, the magnetic coupling between the impeller and the roller becomes abnormal. In the centrifugal liquid pump device of the present invention, when the impeller speed (rotor speed) is 1000 to 3000 rpm, preferably about 1200 rpm, the impeller achieves stable non-contact rotation by the dynamic pressure bearing groove.

The emergency impeller rotation function that operates after detection of a failure will be described in detail below.
In the centrifugal liquid pump device of the present invention, when the failure detection function detects a failure, the current supply to the motor and the electromagnet is stopped, and the impeller rotation is stopped. As a result, the impeller 21 is attracted toward the rotor 31 and approaches the inner surface of the housing 20 by an unbalanced magnetic attraction force from the permanent magnet 33. That is, the impeller 21 is magnetically attracted to the rotor 31 and is captured by a strong frictional force that cannot be freely rotated.

  The impeller magnetic attraction force applying function applies an electric current large enough to overcome the magnetic attraction force of the permanent magnet 33 to the impeller 21 of the rotor 31 to the electromagnet 41 to release the impeller 21 from the rotor 31. When the impeller is weakly coupled to the magnet, the impeller can rotate and the dynamic pressure control mechanism acts. The initial current applied to the electromagnet 41 to generate the attractive force is 10% duty cycle by pulse width modulation (PWM) control, that is, 10% per predetermined time (10% during the predetermined time). It is preferable to do this.

  After applying a 10% continuous (continuous) current to the electromagnetic coil to generate an attractive force, a first attempt is made to start the impeller rotation by applying a predetermined starting voltage of, for example, 4.4 volts to the motor. Do. If the impeller is not rotated by the motor after the first trial, to increase the duration for the suction force, preferably by 1%, for example up to 11% duty cycle, to start the impeller rotation The second trial is performed. This process is repeated until the impeller rotates or until an upper limit of duration percent is reached, eg, 20% in time. That is, the impeller magnetic attraction force applying function in the emergency impeller rotating function has a function of supplying a voltage to the motor with or slightly after the application of the electromagnet current for applying the impeller magnetic attraction force. In other words, the impeller magnetic attractive force applying function can be said to be an impeller magnetic attractive force applying and motor rotation restart function. In particular, in this embodiment, the impeller magnetic attraction force application function (impeller magnetic attraction force application and motor rotation restart function) applies a predetermined motor voltage to the motor and applies a predetermined electromagnet current (predetermined PWM) to the electromagnet. When the impeller does not rotate in the first trial and the first trial, a second trial is performed in which the predetermined motor voltage is maintained and the electromagnet current is gradually increased from the predetermined PWM.

  The dynamic pressure levitation control between the impeller 21 and the rotor 31 can be detected by using the motor current monitored by the dynamic pressure levitation control detection function and the motor current monitoring function for detecting the rotation of the impeller and the rotor. . More specifically, when dynamic pressure levitation control between the impeller 21 and the rotor 31 is achieved, that is, when there is a dynamic pressure bearing coupling, the load on the motor increases. As a result, the motor current increases, and normal gyromagnetic coupling between them can be detected under dynamic pressure bearing conditions.

  The centrifugal liquid pump device of the present invention has a motor speed control function that increases the motor speed to increase the rotation speed of the impeller to a predetermined value (for example, gradually, that is, continuously or stepwise). The motor speed control function operates after the dynamic pressure levitation control detection function detects that the dynamic pressure bearing is coupled between the impeller and the rotor. This motor speed control function increases the motor speed to a predetermined value (at least the motor speed at which the impeller can be rotated substantially in a non-contact manner by the hydrodynamic bearing groove). The centrifugal liquid pump device (in other words, the control mechanism) has a function of storing the motor speed when the failure detection function detects a failure or in the vicinity when the failure detection function detects a failure. It is preferable. The motor speed control function preferably increases the motor speed to the motor speed stored by the motor speed storage function or to a predetermined speed.

  The impeller magnetic attractive force stop function stops the supply of current to the electromagnet 41 when the impeller reaches a predetermined rotational speed. Thus, when the failure detection function detects a failure of the sensor 42 or the electromagnet 41, the emergency impeller rotation function of the centrifugal liquid pump device rotates the rotor 31. At this time, the impeller 21 is in contact with the surface of the housing 20 on the opposite side of the rotor arrangement side by being attracted to the electromagnet 41 by the attraction force. This emergency impeller rotating function releases the state where the impeller 21 is in contact with the inner surface of the rotor-side housing, and preferably shifts the impeller 21 to rotation by a dynamic pressure bearing. After the impeller dynamic pressure control is established, it is not necessary to continue the magnetic attractive force, and therefore the supply of current to the electromagnet is stopped.

The emergency impeller rotation control mode shown in FIG. 8 and its timing as shown in FIGS. 7A and 7B will be described below.
When the failure detection function of the control unit 51 detects a failure of the sensor 42 or the electromagnet 41 (step 11), as shown in FIG. 8, the emergency rotation control mode is started and the operation of the electromagnet and the motor is stopped. (Step 12). Thereafter, the electromagnet duration time is started at a predetermined level, and the impeller 21 and the rotor 31 are brought into a non-contact state. When one or two of the electromagnets, depending on the particular structure, fail, such a situation occurs by using the remaining electromagnets. That is, the pump body of this embodiment includes a plurality (specifically, three) electromagnets. Furthermore, the control function 6 has an electromagnet current monitoring function. Further, the electromagnet current monitoring function in the control function 6 is individually provided so that a failure of each electromagnet can be detected or has only one electromagnet current monitoring function and controls which electromagnet is broken. It is preferable that the part 51 can be determined. Thus, when the control part 51 can identify the electromagnet which failed, the impeller magnetic attraction force provision function operates the function using the electromagnet which has not failed. Further, the control function 6 may be one that can detect a failure of the electromagnet by the electromagnet current monitoring function but cannot identify the failure electromagnet. In this case, the impeller magnetic attractive force imparting function operates as if all the electromagnets have not failed.

Thereafter, in this state, the motor rotates at a predetermined motor voltage. In other words, in Step 13 and Step 14, the motor rotates so that the impeller is not in contact with the rotor. If the motor power is too small, or if the impeller cannot be rotated by the motor due to, for example, high friction, the magnetic attraction force is increased, thereby reducing the impeller frictional force, so that the electromagnet duration time is a fixed amount. Increase by 1%, for example.
The dynamic pressure levitation control detection function of the control unit 51 determines that the impeller levitation coupling has been established, as shown in step 15 of FIG. 8, and the predetermined rotation speed of the impeller has reached a predetermined value, that is, 1200 rpm. At this time, the impeller magnetic attraction force stop function stops the supply of current to the electromagnet 41. Thereafter, the desired rotation of the impeller is maintained in a single fault recovery (SFR) mode, as shown in step 16, and continues to monitor for levitation coupling malfunctions.

  The centrifugal liquid pump device according to the present invention uses the position sensor output monitoring function or the electromagnetic current monitoring function, the motor current monitoring function, and the position sensor output monitoring function to determine a sensor failure, or the electromagnetic current monitoring function. The failure detection function for judging the failure of the electromagnet using the sensor, and when the failure detection function detects the failure of the sensor or the failure of the electromagnet, the impeller and the housing are substantially non-contact using the groove for the hydrodynamic bearing And an emergency impeller rotating function that operates so that the impeller rotates in a state. The emergency impeller rotation function is caused by the rotation stop function for stopping the rotation of the rotor 31 and the impeller 21 and the permanent magnet 33 when the failure detection function detects a failure and stops the supply of electric power to the motor and the electromagnet 41. Impeller and rotor using an impeller magnetic attraction force application function for applying an electric current large enough to overcome the magnetic attraction force of the rotor 31 to the impeller 21 and the motor current monitored by the motor current monitoring function The dynamic pressure levitation control detection function that detects the rotation of the rotor and the dynamic pressure levitation control detection function detect that the hydrodynamic bearing coupling is formed between the impeller and the rotor, and then increase the motor speed to set the rotation speed of the impeller to a predetermined value. Motor speed control function that raises gradually (for example, gradually or stepwise) and impeller rotation speed When it is has reached a predetermined value, and a impeller magnetic attraction force stop function of stopping the supply of electric current to the electromagnet 41.

  Therefore, when trouble occurs in the position sensor or electromagnet that constitutes the control system of the magnetic bearing, or when a failure or other malfunction occurs, rotation using the pressure generated by the groove for the hydrodynamic bearing from the rotation of the impeller by the magnetic bearing Can be moved to. Therefore, the supply of liquid can be maintained.

  In another embodiment, as shown in FIG. 9, an impeller 21 ′ that similarly rotates in a non-contact state with respect to the housing 20 is used. The impeller 21 ′ is substantially the same as the impeller 21 except that there is no dynamic pressure bearing groove 38 provided on the rotor 31 side surface of the impeller 21 ′. Instead, the impeller 21 ′ includes a plurality of dynamic pressure bearing steps 200 on the rotor 31 side, and the inner surface of the housing 20 on the rotor 31 side is substantially smooth. As described above with respect to the impeller 21 in the first embodiment, the impeller 21 ′ does not come into contact with the inner surface of the housing 20 due to the dynamic pressure bearing effect generated between the step 200 and the inner surface of the housing. The blood passage is formed between the bottom surface of the impeller 21 ′ and the inner surface of the housing 20. The function and operation of the centrifugal liquid pump device having the impeller 21 'is the same as the above-described function and operation except that the step 200 is not the dynamic pressure bearing groove 38 but forms the dynamic pressure bearing.

  While preferred forms of the invention have been described, it will be apparent to those skilled in the art that modifications can be made without departing from the spirit of the invention.

FIG. 1 is a block diagram showing a centrifugal liquid pump apparatus according to an embodiment of the present invention. FIG. 2 is a front view showing an example of a main body of the centrifugal liquid pump device of the present invention. FIG. 3 is a plan view showing the main body of the centrifugal liquid pump apparatus of the present invention shown in FIG. FIG. 4 is a longitudinal sectional view showing a main body of the centrifugal liquid pump apparatus of the embodiment shown in FIG. 5 is a cross-sectional view taken along line AA of the main body of the centrifugal liquid pump device shown in FIG. 6 is a cross-sectional view showing a state in which the impeller is removed from the cross-sectional view taken along the line AA of the main body of the centrifugal liquid pump device shown in FIG. FIG. 7 (FIGS. 7A and 7B) is a timing diagram for explaining the operation of the centrifugal liquid pump apparatus according to one embodiment of the present invention. FIG. 8 is a flowchart for explaining the operation of the centrifugal liquid pump apparatus of the present invention. FIG. 9 is a perspective view showing another embodiment of an impeller for a centrifugal liquid pump device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Centrifugal liquid pump apparatus 5 Pump main body 6 Control mechanism 21 Impeller 25 1st magnetic body 28 2nd magnetic body 31 Rotor 33 Magnet 34 Motor 38 Dynamic pressure bearing groove 41 Electromagnet 42 Position sensor 51 Control part 56 Position sensor output Monitoring unit 57 Electromagnetic current monitoring unit

Claims (16)

A centrifugal liquid pump device having a pump body in which an impeller rotates without contacting a housing, and a control mechanism of the pump body,
The pump body includes the housing having a liquid inflow port and a liquid outflow port, a first magnetic body, and a second magnetic body, and rotates the liquid in the housing by centrifugal force generated during rotation. A centrifugal pump unit having the impeller for feeding liquid, a rotor having a magnet for attracting the first magnetic body of the impeller, an impeller rotational torque generating unit having a motor for rotating the rotor, and the impeller An impeller position control unit having an electromagnet for attracting the second magnetic body, a position sensor for detecting the position of the impeller, an inner surface of the housing on the rotor side, or the rotor side of the impeller Hydrodynamic bearing means provided on the surface,
The control mechanism uses a position sensor output monitoring function or an electromagnetic current monitoring function, a motor current monitoring function, and the position sensor output monitoring function to determine a failure of the sensor, or the electromagnetic current monitoring function. A failure detection function for determining a failure of the electromagnet using the dynamic pressure bearing means when the failure detection function detects a failure of the sensor or when the failure detection function detects a failure of the electromagnet. An impeller rotating function for emergency that acts to rotate the impeller without substantial contact between the impeller and the housing,
The emergency impeller rotation function includes: a rotation stop function that stops supply of power to the motor and the electromagnet and stops rotation of the rotor and the impeller when the failure detection function detects a failure; and the magnet The impeller magnetic attraction force applying function that supplies the electromagnet with a current large enough to overcome the magnetic coupling force of the rotor generated by the impeller and the motor current monitored by the motor current monitoring function is used. Then, the dynamic pressure levitation control detection function for detecting the dynamic pressure bearing coupling and thereby detecting the magnetic rotation coupling of the impeller and the rotor under the dynamic pressure bearing condition, and the dynamic pressure levitation control detection function include the impeller And detecting that the hydrodynamic bearing coupling is formed between the rotors, and increasing the motor speed, Accordingly, a motor speed control function for increasing the impeller rotational speed to a predetermined value, and an impeller magnetic attractive force stop function for stopping the supply of current to the electromagnet when the impeller rotational speed reaches the predetermined value. A centrifugal liquid pump device comprising: The said control mechanism has the said position sensor output monitoring function and the said electromagnet current monitoring function, The said failure detection function can judge the failure of the said sensor and the failure of the said electromagnet. Centrifugal liquid pump device. The centrifugal liquid pump device includes a sensor circuit for the sensor, and the sensor circuit has a function of generating an output of a predetermined value exceeding a normal level when the position sensor is disconnected, and the failure detection 3. The centrifugal liquid pump device according to claim 1, wherein the function is to determine whether or not the sensor is out of order based on an output of the sensor monitored by the sensor output monitoring function. The centrifugal liquid pump device includes the electromagnet circuit, the electromagnet circuit is disconnected when the electromagnet is disconnected, and the failure detection function includes the electromagnet current monitoring function and the electromagnet circuit. The centrifugal liquid pump device according to any one of claims 1 to 3, wherein when it is determined that no current flows, the electromagnet is determined to be in failure. When the failure detection function detects a failure, the emergency impeller rotation function balances the magnetic coupling force between the magnet and the impeller of the rotor and the attraction generated by the electromagnet, The centrifugal liquid pump device according to any one of claims 1 to 4, wherein the centrifugal liquid pump device is rotated. 6. The centrifugal liquid pump device according to claim 1, wherein the dynamic pressure bearing means has at least one groove provided on an inner surface of the housing on the rotor side. 6. The centrifugal liquid pump device according to claim 1, wherein the hydrodynamic bearing means has at least one groove provided on a surface of the impeller on the rotor side. 6. The centrifugal liquid pump device according to claim 1, wherein the hydrodynamic bearing means has a plurality of steps provided on a surface of the impeller on the rotor side. The impeller magnetic attraction force imparting function applies a first continuous current to the electromagnet to form attraction, and applies a predetermined voltage to the motor to try to rotate the impeller. The centrifugal liquid pump device according to any one of the above. The impeller magnetic attraction force imparting function further applies a second continuous current to the electromagnet to form the attraction force when the motor fails to rotate the impeller after the first trial. And applying the predetermined voltage to the motor to try to rotate the impeller, wherein the second continuous current is the attraction force formed by the second continuous current is the first continuous current. The centrifugal liquid pump device according to claim 9, wherein the second continuous current is larger than the first continuous current so as to be larger than the suction force formed by. The centrifugal liquid pump device according to claim 10, wherein the second continuous current is larger than the first continuous current by a predetermined step value. The impeller magnetic attraction force applying function is configured to apply an increased continuation current to the electromagnet when the motor fails to rotate the impeller after the first trial and the second trial. Forming and repeatedly rotating the impeller by applying the predetermined voltage to the motor, the increasing continuous current until the impeller rotates or the increasing continuous current reaches a predetermined maximum value, The centrifugal liquid pump device according to claim 11, wherein the increase is repeated in predetermined steps. The centrifugal liquid pump device according to claim 12, wherein the first continuous current is a current corresponding to a 10% time duty cycle of the pulse width modulation control. The centrifugal liquid pump device according to claim 12, wherein the predetermined step value is 1%. The centrifugal liquid pump device according to claim 12, wherein the predetermined maximum value of the increased continuous current is about 20% in time. The pump body includes a plurality of the electromagnets, the electromagnet current monitoring function monitors currents of the electromagnets, and the failure detection function determines at least a failure of the electromagnets. The centrifugal liquid pump device according to any one of claims 1 to 15, wherein the impeller magnetic attractive force imparting function in the emergency impeller rotating function is performed using an electromagnet that is not out of the plurality of electromagnets. .

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